I picked one up this past weekend when I was at REI...
I thought about the Oregon/Montanas, but between the tiny screen and the price, I decided against them.
My wife had a Magellan with a screen that's about the same size as the Oregons and I hated the thing. She has a Garmin Nuvi now, it has a 5" diagonal screen and I would consider that the bare minimum for map reading.
So, I just end up using mine to get my position, the time, elevation, etc and use paper maps.
Operating it is simple, it has 5 buttons - Power/Light, Page/Goto, Enter/Mark, Up, Down. The menus are easy to navigate and use and it has the same basic screens as any other Garmin, just not LCD. The various displays can also be changed just like on the other Garmins.
It also has a magnetic compass and a barometric altimeter. When I was looking at reviews on it, the biggest complaint was the altimeter and the fact that you can't directly view the GPS elevation. Almost all of the complaints were the same, the elevation had to be calbrated daily and they didn't have elevation data to calibrate from.
Apparently, this thing is a little too complicated for those folks - it took me about 30 seconds to figure out that I can calibrate the altimeter using the GPS elevation and if I really need a dead-nuts-on elevation fix, it takes less than 30 seconds to calibrate it to the GPS elevation. Stupidly simple, but maybe that's just me...
Anyways, I like the thing alot so far. Compared to the Rino 120 I already have, the 401 is about 1/3 the size, 1/3 the weight and the battery life is already proving to be far better.
I left it in my truck Sunday night and forgot to turn it off, so doing an impromptu test of it. Oh, and I put lithiums (AAA) in it (another good suggestion from you guys, thanks).
The next morning, after being on for 11 hours straight, plus about another hour and a half of playing with it over the weekend, the battery indicator had only dropped by one bar. My Rino would have burned up 3 alkaline AAAs in the same amount of time.
So, if you're like me and just want a plain jane, simple GPS, I would definitely recommend looking at the 401.